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Shaded-pole induction motors (SPIMs) are extensively used in industrial applications, home appliances and ventilation systems due to their simple structure, low cost and low maintenance requirement. Formation of elliptic rotating field in SPIM makes its analysis rather complex. As the result of this complexity, there are relatively limited publications on the theory, design and analysis for this kind of motor. In many cases, its design is based on trial and error method. As it is appreciated, the accuracy of predicted performance of electric machines is closely related to the accuracy of the winding inductances used in calculations. For this reason, in this study, stator and shading-rings end-winding leakage inductance, stator winding self-inductance, total leakage inductance of the stator winding and the mutual inductance between stator and rotor winding of a 4-pole SPIM are obtained by means of the derived analytical equations and real-time experiments. Also, the effect of magnetic saturation on the stator self and leakage inductances, and the variation of stator-rotor mutual inductance with respect to the rotor position have been investigated. At the end of the study, the accuracy of computed stator winding self-inductance is validated by an experimental exercise.

Fractional pole‐ratio winding is a new type of AC winding, consisting of coils with different pitches. The application of fractional pole‐path ratio windings in synchronous generators will bring new problems to the modelling and simulation of internal faults. It is important to establish a mathematical model for the fractional pole‐path ratio synchronous generators with internal faults and accurately calculate the fault currents. In this study, the multi‐loop model of fractional pole‐path ratio synchronous generators is first proposed. The method for calculating mutual inductances between stator coils with arbitrary pitch is given, and all the space harmonics, including the fractional ones, are considered in the inductance calculation. In order to improve the simulation accuracy of turn‐to‐turn faults, the effect of core localised saturation is modelled by modifying the air gap function of fault coils. A 300 MW fractional pole‐path ratio synchronous generator is set as an example, and three types of internal faults are simulated. The comparisons of simulation results are made between the multi‐loop model and the finite element model to verify the validity of the multi‐loop model proposed in this study. [ABSTRACT FROM AUTHOR]

The brushless doubly fed induction machine (BDFM) is considered as an alternative to doubly fed induction generators (DFIGs) in wind energy conversion systems. However, BDFMs have a complex machine structure, and their operations are relatively complicated. In this study, the winding function theory is used in the development of a coupled circuit (CC) model for BDFMs with nested loop (NL) and cage+NL rotors, in order to give a robust representation of the electrical operations of BDFMs. The electrical circuit analysis of BDFMs having NL and cage+NL rotors is comprehensively detailed, with the stator and rotor inductances calculated using their winding functions. The interactions of BDFM rotor loops with stator windings are demonstrated in terms of mutual inductances. CC models of different BDFMs are simulated for synchronous doubly fed BDFM operations with an emphasis on generating regions. Also, fresh insight into the torque production in BDFMs is provided, with the rotor loops and stator winding contributions to torque magnitude and ripple examined. [ABSTRACT FROM AUTHOR]

Dynamic wireless power transfer (DWPT) is a promising solution to address electric vehicle range anxiety and to reduce the capacity and the cost of the on-board batteries. In the traditional DWPT system, the mutual inductances among the transmitters make the design of compensation networks very complex. Besides, the power null phenomenon and the power pulsation phenomenon cause a fluctuating dc output voltage or current on the receiver side. To address these issues, this paper proposes a new magnetic coupler. Unipolar and bipolar coils are laid alternately to form segmented transmitters, which are turned on or off according to the position of the overhead receiver coil. LCC compensations, whose inputs are connected in parallel to a common inverter for cost reduction, are adopted. At the receiver side, unipolar and bipolar coils are overlapped in the same plate in order to effectively smooth out the mutual inductance variations and, hence, reduce the output voltage or current fluctuations. Also, a configurable resonant circuit is designed on the receiver side to achieve constant voltage charging and constant current charging. Moreover, an optimization design by using finite-element analysis software Maxwell is developed to choose the best turns of the receiver coil to further improve the output quality. A laboratory prototype with 4-A charging current and 96-V charging voltage, using 85 kHz operation frequency, is constructed to verify the proposed DWPT system. The experimental results show that constant and stable output voltage and current can be achieved with only ±2% fluctuation, and the overall efficiency is 90.37%. [ABSTRACT FROM AUTHOR]

In this study, a novel modular three-phase permanent magnet synchronous motor (PMSM) is proposed for low-voltage high power applications. The proposed modular three-phase PMSM has an independent segregated three-phase winding configuration, facilitating the implementation of the control algorithm. Firstly, on the basis of the electromagnetic properties, the mathematical model of the modular three-phase PMSM is established, considering the asymmetrical mutual inductances investigated by finite element analysis (FEA). Then, the predictive torque control (PTC) method combining the inductance characteristics of modular three-phase PMSM is developed, and excellent performance is obtained by adjusting the stator flux and torque. Finally, simulation and experiment are performed, and the results show that the proposed novel modular three-phase PMSM with the PTC method exhibits excellent control performance, and small stator current total harmonic distortion (THD).

A new analytical solution for the self‐ and mutual inductances of arbitrary triangular coils with rectangular cross‐section is presented. Firstly, the electromagnetic field problem of a filamentary triangular coil is solved based on second‐order vector potential. Then, the solution is effectively extended to the arbitrary triangular coil with different track widths by changing the radius of its inscribed circle. A series of new formulae are given for calculating electromagnetic field, self‐ and mutual inductances of triangular coils with different shapes, separation distances, lateral misalignments or angular misalignments. Finally, the verification experiments are carried out on a series of irregular and regular triangular coils. Also, the experimental results show that the measured values are in good accordance with the calculated ones. [ABSTRACT FROM AUTHOR]

This paper aims to present innovations in design of a Switched Reluctance Generator in settings 6x4 and 6x6. A specific methodology for generators design is proposed, based on the study of magnetic saturation and mutual inductances influences. These studies, when compared to classical methodology design, indicate the need for modifications on structure and dimensions of these converters with the intention to increase the efficiency. The proposed modifications cause a significant increment on magnetic saturation and mutual inductances at excitation period. This saturation increasing decreases the magnetic flux variation, causing the reduction of required torque to spin the generator rotor. So, the decrease of this required torque provokes the increasing efficiency. A bench test is built to validate the simulations results. [ABSTRACT FROM PUBLISHER]

In this paper, a three‐phase dual armature‐winding doubly fed doubly salient electromagnetic generator (DAW‐DFDSEG) is proposed. The reason for using different numbers of turns in the two sets of armature windings is presented. On the basis of the finite‐element method (), two different DAW structures (DAW1 and DAW2) with different turn numbers of armature windings are analysed and compared. The DAW2 structure outputs more power than DAW1 under the same turn number of armature windings, due to the stronger flux‐weakening armature reaction under heavy magnetic saturation. However, the manufacturing technique of DAW2 is more complex than that of DAW1 in the limited stator slot. The DAW1 with two set armature windings of 11 and 12 is researched in detail in terms of flux linkage, induced voltages, winding voltages, winding currents, self‐inductances and mutual inductances by simulation and the equivalent rectifier circuit patterns of two time zones are also presented. Meanwhile, its commutation procedure is analysed in detail. To validate the analysis, a 12/8‐pole DAW‐DFDSEG prototype has been designed and the simulated waveforms agree well with the measured ones. [ABSTRACT FROM AUTHOR]

This paper proposes a decoupled d-q model of double-star interior-permanent-magnet (IPM) machines, whose stator consists of two three-phase winding sets displaced by an arbitrary angle. The model is based on the elaboration of the inductance parameters and is obtained by deriving a transformation that diagonalizes the original 6 x 6 stator inductance matrix of the machine. In the derivation of the transformation, the common assumption of the regularity of the mutual inductances between the two three-phase sets is omitted. Thus, the transformation diagonalizes the stator inductance matrix even if the mutual inductances do not have specific symmetry. It is demonstrated that in order to obtain decoupled reference frames in such a case, the transformation depends on the machine parameters. The validity of the machine model is verified by experimental tests with a double-star IPM machine, in which the two three-phase winding sets are displaced by 30 electrical degrees. [ABSTRACT FROM AUTHOR]

A toroidal field coil is composed of several individual toroidal coils (ITCs) which are connected in a series and distributed in a toroidal and symmetrical form. Cross section of ITCs is rectangular or negligible. This paper presents analytical equations of mutual inductance of two ITCs applicable to tokamak reactors using the filament method. These equations are based on those formulated by Neumann. The numerical analysis of the integrations resulting from these equations is solved using the extended three-point Gaussian algorithm. The finite element method (FEM) is employed to verify the mutual inductance equations of ITCs. The results obtained using FEM, when dimensional parameters of ITCs are changed, confirm the analytical and empirical results showing an error of less than 0.2043% in the worst case. This indicates the reliability of the presented equations. This paper also employs FEM to obtain depth of penetration of electromagnetic waves in high-conductivity conductors (HCCs). The results show that the ratio of real depth of penetration, obtained by FEM, to ideal depth of penetration in HCCs is independent of frequency. This ratio shows that the magnitude of traveling plane waves in HCC decreases with e^-1.7916 rather than e^-1. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with the speed control of switched reluctance motor (SRM) drives taking into account the effects of the mutual inductances between two adjacent phases and the effects of the magnetic saturation of the core. To overcome the problems commonly associated with single-phase excitation, a nonlinear SRM model, which is suitable for two-phase excitation and which takes into account the effects of mutual inductances between two adjacent phases and the magnetic saturation effects, is considered in the design of the proposed controllers. A feedback linearization control scheme and a sliding mode control scheme are designed for this motor drive. The proposed controllers guarantee the convergence of the phase currents and the rotor speed of the motor to their desired values. Simulation results indicate that the proposed controllers work well and that they are robust to changes in the parameters of the system and to changes in the load torque. [Copyright &y& Elsevier]

This paper proposes a new method to minimize torque ripple of a switched reluctance motor (SRM), which is based on the control of the sum of the square of the phase currents by using only two current sensor and analog multipliers. In addition, the sliding mode control (SMC) technique has been applied to SRM speed control loop that compensates the low frequency oscillations on the torque output. The applied sliding mode controller adjusts the value of the reference current to keep the speed of the motor constant. The proposed sliding mode continuous controller performs better than PI and Fuzzy controllers and is also more robust to the external disturbances. The results show that the continuous sliding mode controller is effective compared to PI or Fuzzy controllers in reducing the torque ripple of the motor, compensating for the nonlinear torque characteristics and making the drive insensitive to parameter variations as well. Since, mutual inductances have an important disturbance effect on the torque ripple, mathematical model of the SRM has been derived in presence of them. It has been used a completely analog system to implement the proposed algorithm. Also, a mechanical sensor has been used to sense the rotor position. Simulation and experimental results are given to validate the proposed method for the self and mutual inductances and current measurements. [Copyright &y& Elsevier]

In this study, a novel modular three-phase permanent magnet synchronous motor (PMSM) is proposed for low-voltage high power applications. The proposed modular three-phase PMSM has an independent segregated three-phase winding configuration, facilitating the implementation of the control algorithm. Firstly, on the basis of the electromagnetic properties, the mathematical model of the modular three-phase PMSM is established, considering the asymmetrical mutual inductances investigated by finite element analysis (FEA). Then, the predictive torque control (PTC) method combining the inductance characteristics of modular three-phase PMSM is developed, and excellent performance is obtained by adjusting the stator flux and torque. Finally, simulation and experiment are performed, and the results show that the proposed novel modular three-phase PMSM with the PTC method exhibits excellent control performance, and small stator current total harmonic distortion (THD). [ABSTRACT FROM AUTHOR]